Elsewhere in the province, two home-made bombs exploded outside the house of the provincial chief minister, and militants blew up a natural gas pipeline, but there were no casualties in these incidents.
Sunday's violence happened as up to 1500 pro-government Rahija tribesmen returned to their home in the nearby town of Dera Bugti under tight security cover from government forces.
Officials said the militants attacked paramilitary Frontier Constabulary (FC) troops with rockets and small arms near Loti, where a natural gas field run by the state-owned Oil and Gas Development Co Ltd is.
Lieutenant-Colonel Furqan-ud-din of the FC told reporters in Dera Bugti: "After brief fighting, one of our soldiers was martyred and we killed two miscreants."
He said two militants were wounded and had been arrested.
Two bombs exploded near the house of chief minister Jam Mohammad Yousuf in Lasbela, about 400km southwest of Dera Bugti, demolishing a wall of the house, a provincial government spokesman said.
Yousuf was not in the house at the time of the attack.
Furqan-ud-din blamed supporters of renegade tribal leader Nawab Akbar Bugti for the attack near Loti and said they intended to disrupt the return of Rahijas to their homeland.
"The attackers belonged to the private militia of Akbar Bugti," he said.
The latest rise in violence in Baluchistan follows a crackdown by Pakistani security forces on Baluch rebels after a rocket attack on 14 December when Pervez Musharraf, the Pakistani president, was visiting the town of Kohlu in the area.
The unrest in the province, which also borders Iran, is another pressing security problem for Musharraf, whose forces are also battling al-Qaida-linked militants in tribal areas on the Afghan border to the north of Baluchistan.